The Base of a Certain Solid Is a Plane Region $y = 1 - x ^ { 2 }$

Short Answer

The base of a certain solid is a plane region R enclosed by the x-axis and the curve $y = 1 - x ^ { 2 }$ . Each cross-section of the solid perpendicular to the y-axis is an isosceles triangle of height 4 with its base lying in R. Find the volume of the solid.